(CNN) -- Two U.S. soldiers whose signatures appeared on an op-ed piece in The New York Times critical of the war in Iraq were among seven Americans killed in a truck accident outside of Baghdad, family members said Wednesday.

Iraqi National Security Adviser Muwaffaq al-Rubaie said Wednesday he will support 2008 decrease in U.S. troops.

Staff Sgt. Yance Gray and Sgt. Omar Mora were members of the Army's 82nd Airborne Division, based at Fort Bragg, North Carolina.

Gray, Mora and five other soldiers died Monday when their truck overturned near the Iraqi capital, U.S. officials said.

Gray and Mora were among seven soldiers, mostly sergeants, who wrote the op-ed piece that appeared in the Times on August 19. It called the prospects of U.S. success "far-fetched" and said the progress being reported was being "offset by failures elsewhere."

"Four years into our occupation, we have failed on every promise, while we have substituted Baath Party tyranny with a tyranny of Islamist, militia and criminal violence," they wrote. "When the primary preoccupation of average Iraqis is when and how they are likely to be killed, we can hardly feel smug as we hand out care packages."

Gray, 26, joined the Army out of high school in Ismay, Montana, in 2000, said his father, Richard Gray. Yance Gray is survived by a wife and daughter.

A relative at Mora's family home in Texas City, Texas, confirmed his death but had no other comment.

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In their article, Mora, Gray and their comrades wrote that American troops in Iraq are operating "in a bewildering context of determined enemies and questionable allies, one where the balance of forces on the ground remains entirely unclear."

However, they concluded, "As committed soldiers, we will see this mission through."

Another of the signers of the Times article, Staff Sgt. Jeremy Murphy, was shot in the head a week before the article appeared but survived.

Meanwhile, a top Iraqi official said he foresees a decrease in foreign troop levels to less than 90,000 by the end of 2009 as Iraq bolsters and readies its security forces to take over responsibilities now being shouldered by the U.S.-led coalition forces.

The U.S. troop increase this year, dubbed "the surge" by the Bush administration, added nearly 30,000 troops to Iraq. The number of U.S. troops at present is more than 160,000 and the number of other coalition forces is more than 11,000.

National Security Adviser Mowaffaq al-Rubaie, speaking at a Wednesday press conference, told reporters that by next year the number of foreign troops might drop to about 130,000, the pre-surge level, or to 100,000 troops.

"When we reach 2009, we could talk about numbers that are less than 90,000" among the Multi-National Force, said al-Rubaie, who emphasized that such withdrawals would depend on the security environment and troop readiness.

Al-Rubaie made the remarks a day after senior U.S. administration officials said that President Bush is prepared to embrace the recommendation of his top commander in Iraq, Gen. David Petraeus, and withdraw as many as 30,000 U.S. troops by next summer.E-mail to a friend